Moisture-responsive supramolecular nanotubes
Moisture-responsive supramolecular nanotubes
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DOI：
10.1039/c8nr05748f
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发表时间：
2018-11-21
期刊：
影响因子：
6.7
通讯作者：
Kogiso, Masaki
中科院分区：
文献类型：
--
作者：
Ding, Wuxiao;Wu, Dongwei;Kogiso, Masaki
随着湿度的变化，生物进化出了种子传播的功能结构。在这项研究中，我们通过肽脂与金属离子的超分子配位构建了水分响应纳米管，在材料输送系统中具有潜在的应用前景。这些亲水性纳米管可以吸收大气中的水分，并且水分子与双（脂）-金属（ii）络合物的不饱和金属中心相结合，从而改变分子堆积并诱导从纳米管到薄片的形态转变。纳米管的水分响应性取决于金属离子的水化行为。由于Co（ii）离子与水分子的结合更强，Co（ii）配位纳米管的水分响应性比Zn（ii）配位纳米管高。这两种纳米管是由相同的分子填料自组装的；然而，它们在形态变化中表现出不同的机制。Co（ii）配位纳米管转变成薄片，同时伴随着络合物和反分子填料的破坏，而Zn（ii）配位纳米管转变成薄片，同时伴随着复杂几何结构的变化。此外，Co（ii）配位纳米管在纳米管和纳米片之间表现出可逆的形态变化，而Zn（ii）配位纳米管表现出单向的形态变化。这些纳米管在高湿度环境下释放香精油方面也有潜在的应用。
Living organisms have evolved functional structures for seeds dispersal in response to humidity changes. In this study, we construct moisture-responsive nanotubes by the supramolecular coordination of a peptide lipid with metal ions for potential applications in material delivery systems. These hydrophilic nanotubes can uptake atmospheric moisture and the water molecules are associated with unsaturated metal centers of the bis(lipid)-metal(ii) complex, thereby changing the molecular packing and inducing morphological transformation from nanotubes to sheets. The moisture responsivity of nanotubes depends on the hydration behavior of the metal ions. Co(ii)-coordinated nanotube shows higher moisture responsivity than that of the Zn(ii)-coordinated one since Co(ii) ion has stronger association with water molecules. These two nanotubes are self-assembled by the same molecular packings; however, they show different mechanisms in morphological changes. The Co(ii)-coordinated nanotube transforms into a sheet accompanied with the destruction of the complex and reverse molecular packing, whereas Zn(ii)-coordinated nanotube transforms into a sheet with a change in the complex geometry. Further, the Co(ii)-coordinated nanotubes exhibit reversible morphological changes between nanotubes and sheets, while Zn(ii)-coordinated nanotubes exhibit a one-way morphological change. These nanotubes also show potential applications in the release of fragrance oil under high humidity environments.